adverse

adjective

ad·​verse ad-ˈvərs How to pronounce adverse (audio)
ˈad-ˌvərs
1
: acting against or in a contrary direction : hostile
hindered by adverse winds
2
a
: opposed to one's interests
an adverse verdict
heard testimony adverse to their position
especially : unfavorable
adverse criticism
b
: causing harm : harmful
adverse drug effects
3
archaic : opposite in position
adverseness noun

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Adverse vs. Averse

Many people find themselves confused when faced with the choice between adverse and averse. While these two adjectives have many similarities, they are not used interchangeably.

If you want to describe a negative reaction to something (such as a harmful side effect from medication) or dangerous meteorological conditions (such as a snowstorm), adverse is the correct choice; you would not say that you had an averse reaction to medication or that there was averse weather.

Averse is most commonly followed by the preposition to (as in "she is averse to shellfish"), but not in every case; you can, for example, describe someone as “risk averse." Normally, averse to signifies a degree of dislike and avoidance, but when preceded by the word not (as in “he was not averse to having another drink”), it may be used as a pointedly understated way to express an interest in something.

In short, adverse tends to be used to describe effects, conditions, and results; while averse refers to feelings and inclinations.

Examples of adverse in a Sentence

The Bankruptcy Code requires that debtor's counsel be disinterested and not have an interest adverse to the estate. Lawyers Weekly USA, 4 Oct. 1999
On more than one occasion his decrees provoked riots, and there were those who voiced adverse opinions on the Duke in public. Alison Weir, The Princes in the Tower, 1992
The plant tolerates adverse conditions … Dave Dunn, Fine Gardening, January/February 1991
all the adverse publicity really caused the movie star's popularity to suffer the adverse effects of the drug are too severe to allow it to be marketed
Recent Examples on the Web Though no illnesses have been reported in association with these cinnamon products yet, long-term exposure to lead can lead to adverse health effects, especially in children. Korin Miller, Health, 8 Mar. 2024 Long-term exposure - meaning months to years - to elevated levels of lead in the diet could contribute to adverse health effects, particularly for the portion of the population that may already have elevated blood lead levels from other exposures to lead. Chad Murphy, The Enquirer, 7 Mar. 2024 Consultation with healthcare professionals is vital before consuming excessive amounts of supplements, especially magnesium, to avoid adverse effects or potential interactions. Anthony De Leon, Los Angeles Times, 7 Mar. 2024 This compounds lead’s adverse effects as our bodies grow and age, since the lead in bone will reappear as our body looks to its calcium stores during periods of growth or, critically, during pregnancy. Aaron Specht, The Conversation, 7 Mar. 2024 In its paper, Cognito highlighted that its treatment did not cause these adverse events or other serious side effects. Emily Mullin, WIRED, 6 Mar. 2024 Honing the craft Despite his strong 2023 campaign, Vaz still had to overcome some adverse moments. Jaylon Thompson, Kansas City Star, 6 Mar. 2024 The pop superstar's first of four nights at the stadium kicked off shortly before 8 p.m. local time following a delay due to adverse weather. Brendan Le, Peoplemag, 23 Feb. 2024 President Joe Biden has taken a dual track approach to provide student loan borrowers with relief following the Supreme Court’s adverse ruling last summer striking down his signature debt cancellation program. Adam S. Minsky, Forbes, 26 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'adverse.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Middle English, borrowed from Anglo-French advers, borrowed from Latin adversus "turned toward, facing, opposed," from past participle of advertere "to turn toward, direct" — more at advert entry 1

First Known Use

14th century, in the meaning defined at sense 1

Time Traveler
The first known use of adverse was in the 14th century

Dictionary Entries Near adverse

Cite this Entry

“Adverse.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/adverse. Accessed 19 Mar. 2024.

Kids Definition

adverse

adjective
ad·​verse ad-ˈvərs How to pronounce adverse (audio)
ˈad-ˌvərs
1
: acting in an opposite direction
adverse winds
2
: opposed to one's interests
adverse testimony
especially : not friendly or favorable
adverse criticism
3
: causing harm
adverse effects of a drug
adversely adverb
adverseness noun

Legal Definition

adverse

adjective
: opposed to one's interests : operating to one's detriment
an adverse verdict

More from Merriam-Webster on adverse

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